A way to avoid bubble formation in photoelectrolysis systems – which split water into hydrogen and oxygen – so that water vapour can be electrolysed at room temperature at current densities in excess of those produced by the best photoelectrolysis systems has been developed by US scientists.
The formation of hydrogen through water electrolysis is one viable approach for solar fuel production on a global scale. Although photovoltaic modules can be connected to conventional electrolysers to split water, photoelectrolysis systems, in which sunlight is absorbed and the energy directly converted to decompose water to hydrogen and oxygen, have the potential to be more inexpensive and efficient.
An efficient photoelectrolyser, however, tends to limit its own performance by the formation of copious bubbles of gaseous products that inhibit the process by reflecting light and slowing the transfer of water to the catalyst reaction sites. Without concentrators, the intensity of the solar photon flux limits photoelectrolysers to far lower current densities than are used in conventional electrolysers.
Read this paper hot off the press!
Reference:
J M Spurgeon and N S Lewis, Energy Environ. Sci., 2011
DOI: 10.1039/c1ee01203g
